283 research outputs found
Additional file 1 of Short-term effects of ambient temperature on the risk of preeclampsia in Nanjing, China: a time-series analysis
Additional file 1: Supplemental Material A. Table S1 The cumulative effects estimated for different temperatures (25th percentile and 75th percentile) at different lag days with the reference temperature. Table S2 Model parameter selection for different lag days. Supplemental Material B. Table S3 Model parameter selection for different degrees of freedom of RH, SO2, NO2, CO, O3, PM10 and PM2.5. Supplemental Material C. Table S4 The total cumulative effects of relative risk for different degree of freedom of RH, SO2, NO2, CO, O3, PM10 and PM2.5 with temperature (25th percentile). Table S5 The total cumulative effects of relative risk for different degree of freedom of RH, SO2, NO2, CO, O3, PM10 and PM2.5 with temperature (75th percentile)
Open-Shell Tensor Hypercontraction
The extension of least-squares tensor
hypercontracted
second- and
third-order Møller–Plesset perturbation theory (LS-THC-MP2
and LS-THC-MP3) to open-shell systems is an important development
due to the scaling reduction afforded by THC and the ubiquity of molecular
ions, radicals, and other open-shell reactive species. The complexity
of wavefunction-based quantum-chemical methods such as Møller–Plesset
and coupled cluster theory is reflected in the steep scaling of the
computational costs with the molecular size. The least-squares tensor
hypercontraction (LS-THC) method is an efficient, single-step factorization
for the two-electron integral tensor but can also be used to factorize
the double excitation amplitudes, leading to significant scaling reduction.
Here we extend this promising method to open-shell variants of LS-THC-MP2
and -MP3 by using diagrammatic techniques and explicit spin summation.
The accuracy of the resulting methods for open-shell species is benchmarked
on standard test systems such as regular alkanes as well as realistic
systems involving bond breaking, radical stabilization, and other
effects. We find that open-shell LS-THC-MPn methods
exhibit errors highly comparable to those produced by closed-shell
LS-THC-MPn and are highly insensitive to particular
chemical interactions, geometries, or even moderate spin contamination
Open-Shell Tensor Hypercontraction
The extension of least-squares tensor
hypercontracted
second- and
third-order Møller–Plesset perturbation theory (LS-THC-MP2
and LS-THC-MP3) to open-shell systems is an important development
due to the scaling reduction afforded by THC and the ubiquity of molecular
ions, radicals, and other open-shell reactive species. The complexity
of wavefunction-based quantum-chemical methods such as Møller–Plesset
and coupled cluster theory is reflected in the steep scaling of the
computational costs with the molecular size. The least-squares tensor
hypercontraction (LS-THC) method is an efficient, single-step factorization
for the two-electron integral tensor but can also be used to factorize
the double excitation amplitudes, leading to significant scaling reduction.
Here we extend this promising method to open-shell variants of LS-THC-MP2
and -MP3 by using diagrammatic techniques and explicit spin summation.
The accuracy of the resulting methods for open-shell species is benchmarked
on standard test systems such as regular alkanes as well as realistic
systems involving bond breaking, radical stabilization, and other
effects. We find that open-shell LS-THC-MPn methods
exhibit errors highly comparable to those produced by closed-shell
LS-THC-MPn and are highly insensitive to particular
chemical interactions, geometries, or even moderate spin contamination
Open-Shell Tensor Hypercontraction
The extension of least-squares tensor
hypercontracted
second- and
third-order Møller–Plesset perturbation theory (LS-THC-MP2
and LS-THC-MP3) to open-shell systems is an important development
due to the scaling reduction afforded by THC and the ubiquity of molecular
ions, radicals, and other open-shell reactive species. The complexity
of wavefunction-based quantum-chemical methods such as Møller–Plesset
and coupled cluster theory is reflected in the steep scaling of the
computational costs with the molecular size. The least-squares tensor
hypercontraction (LS-THC) method is an efficient, single-step factorization
for the two-electron integral tensor but can also be used to factorize
the double excitation amplitudes, leading to significant scaling reduction.
Here we extend this promising method to open-shell variants of LS-THC-MP2
and -MP3 by using diagrammatic techniques and explicit spin summation.
The accuracy of the resulting methods for open-shell species is benchmarked
on standard test systems such as regular alkanes as well as realistic
systems involving bond breaking, radical stabilization, and other
effects. We find that open-shell LS-THC-MPn methods
exhibit errors highly comparable to those produced by closed-shell
LS-THC-MPn and are highly insensitive to particular
chemical interactions, geometries, or even moderate spin contamination
MOESM1 of The association between health professionals’ international experience and the academic output of their students in Harbin, China
Additional file 1: Table S1. Questionnaire which was administered to 257 students of ‘returning’ professionals
Data_Sheet_1_Effect of Heat Treatment on the Property, Structure, and Aggregation of Skim Milk Proteins.PDF
To study the mechanism of heat-induced protein aggregates, skim milk was heated at 55, 65, 75, 85, and 95°C for 30 s. Then, the sulfhydryl content, surface hydrophobicity, and secondary structure of heat-treated skim milk were studied. Treating skim milk at different temperatures induced a decrease in sulfhydryl content (75.9% at 95°C) and an increase in surface hydrophobicity (44% at 95°C) with a disrupted secondary structure containing random coil, β-sheet, and β-turn of skim milk proteins. The change in these properties facilitated aggregate formation through disulfide bonds and hydrophobicity interaction. Microstructural observation also showed a higher degree of aggregation when skim milk was heated at 85 and 95°C. The result of two-dimensional polyacrylamide gel electrophoresis demonstrated that the aggregates consisted of a high proportion of κ-casein, β-lactoglobulin, and other whey proteins.</p
<i>De Novo</i> Cleaning of Chimeric MS/MS Spectra for LC-MS/MS-Based Metabolomics
The purity of tandem mass spectrometry (MS/MS) is essential
to
MS/MS-based metabolite annotation and unknown exploration. This work
presents a de novo approach to cleaning chimeric
MS/MS spectra generated in liquid chromatography–tandem mass
spectrometry (LC-MS/MS)-based metabolomics. The assumption is that
true fragments and their precursors are well correlated across the
samples in a study, while false or contamination fragments are rather
independent. Using data simulation, this work starts with an investigation
of the negative effects of chimeric MS/MS spectra on spectral similarity
analysis and molecular networking. Next, the characteristics of true
and false fragments in chimeric MS/MS spectra were investigated using
MS/MS of chemical standards. We recognized three fragment peak attributes
indicative of whether a peak is a false fragment, including (1) intensity
ratio fluctuation, (2) appearance rate, and (3) relative intensity.
Using these attributes, we tested three machine learning models and
identified XGBoost as the best model to achieve an area under the
precision–recall curve of 0.98 for a clear separation between
true and false fragments. Based on the trained model, we constructed
an automated bioinformatic platform, DNMS2Purifier (short for de novo MS2Purifier), for metabolic features from metabolomics
studies. DNMS2Purifier recognizes and processes chimeric MS/MS spectra
without additional sample analysis or library confirmation. DNMS2Purifer
was evaluated on a metabolomics data set generated with different
MS/MS precursor isolation windows. It successfully captured the increase
in the number of false fragments from the increased isolation window.
DNMS2Purifier was also compared to MS2Purifier, an existing MS/MS
spectral cleaning tool based on the addition of data-independent acquisition
(DIA) analysis. Results indicated that DNMS2Purifier uniquely recognizes
false fragments, which complements the previous DIA-based approach.
Finally, DNMS2Purifier was demonstrated using a real experimental
metabolomics study, showing improved MS/MS spectral quality and leading
to an improved spectral match ratio and molecular networking outcome
Additional information of PCA and MSM analysis.
(A) PCA scree plot: dot shows the cumulative explained variance of the principal components; the bar chart represents the explained values per component. (B) Relaxation timescales of MSM for SH2 domain conformational space at different lag times. (C) The first ten features that contribute the first two PC the most. The absolute value of PC1 and PC2, and square root of sum of squared PC1 and PC2 values are shown here. (TIF)</p
Additional REDAN analysis results.
(A) Proposed pathway from 170 to 640 shown in the protein structure; (B) Proposed pathway from 170 to 644; (C,D,E) Key pair residue distance; (F) Ramachandran Dihedral for residue 513,514, 515 and 517; (G) Summary of proposed pathways from source residue 170 to target residue 640,644 and 657. (TIF)</p
STAT3 structure.
1BG1 was used as the template; NTD is not shown. (A) STAT3 domain structure (Y705 is shown as spheres, D170 is shown as sticks). Vide infra for details of the initial structure.(B) Secondary structures are labeled according to the UniProt database (S1 Table) [6]: α helices are colored blue, β sheets are colored red, and unstructured regions (loops) are colored yellow (transverse view). The assigned secondary structures combine information from multiple x-ray crystal structures, thus there is some mismatch with the specific structures used in this work.</p
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